1. Field of the Invention
This invention relates generally to the field of computer graphics and, more particularly, to a high performance graphics system which may enable video rate displacement mapping.
2. Description of the Related Art
Displacement mapping has been used in off-line applications to add fine geometric detail to a three-dimensional rendered object. It may be used in a similar manner to the more widely implemented “bump mapping,” but provides more accurate silhouette edges and shadows.
Displacement mapping involves tessellating a three-dimensional model and determining a surface normal for each of a specified set of points. For each of these points a corresponding location in a displacement map may be determined and used to access a displacement value from a pre-computed, stored table. The table value is treated as a distance and the surface point may be displaced in the direction of the normal vector by a scalar multiple of the table value. Displacement mapping may be used to emboss a flat surface by modeling the flat surface and encoding the pattern to be embossed into a displacement map.
Pixar's Photo-realistic Renderman™ software product provides off-line displacement mapping.